Timing belt riding over and shredding

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toms3

Active Member
Posts
375
Location
west yorkshire
Well last year my timing belt snapped as it run against the casing and shredded itself then snapped. It looked as tho it took a while as when I took it apart the casing was full of dust and bits of belt. I carefully re-fit a new timing belt kit with new pulley and idler.

This morning while doing my regular look underneath I peered through the wading plug hole on the timing casing with a torch and saw a bit of chewed up belt. A poke around with a fine screwdriver I managed to fish this lot out....



Gutted is an understatement!!! What could have caused this to happen twice, iv done 8000 miles since I changed the belt so it should have lots of life in it yet!

Any information or advice why this could happen would be great as I'm at my wits end now with it and want to sort it once and for all as it's also my daily. I was wondering if there is such thing as modified pulleys or Idlers or something like that?

Your help would be much appreciated!

Cheers, tom.
 
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Here's a pic of the belt fitted last time it was changed......



I can't see anything wrong but I'm still learning theese things still. Iv zoomed in and all looks ok?

Here is a pic of the front casing when it was removed the 1st time round.....

 
You have the old type crank pulley and tensioner fitted. It was updated so the crank pulley has the flanges and the tensioner doesn't. Done to stop what you are experiencing. Some spares places do mod kits to replace all the superseded parts. Includes pulleys, bearing, tensioner and stud/nut. Time to change it again unfortunately. Note belt tension has also been changed (reduced). Do some searching on here - plenty of info.
 
Thanks kwakerman much appreciated. I understand the crank pulley the one at the bottom right of the pic, and the tensioner to the left of it?, so I should be looking for a crank pulley with a flange on it?

Iv been searching most of the afternoon but I am struggling with it all to be honest.
 
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I have searched on Google too to find out about updated flanged pulleys and any updated kits and I am struggling to find out anything about them, I don't suppose anyone could point me in the right direction?

Cheers, tom.
 
I have searched on Google too to find out about updated flanged pulleys and any updated kits and I am struggling to find out anything about them, I don't suppose anyone could point me in the right direction?

Cheers, tom.

they are for the 300 tdi , its worth undoing injection pump support bracket and resecuring ensuring its not pulling on rear of the pump it can cause misalignment
 
No wonder I couldn't find anything about the flanged pulleys, I been researching most of the day expecting something like that and found none.

It's a bit frustrating as I took my time and thaught I'd done a good job!

I'm just waiting for parts to arrive and hopefully tackle it at the weekend.

Thanks jamesmartain I shall try that when I install the new belt, is that the only thing that could cause the belt to pull over?

Thank you.
 
I would agree with James look at the cover and you can see where the belt has ridden up first causing the biggest shiniest bit.
Not seen this on a 200 but have had it on a 300
Also worth running it for a few seconds with the timing cover off to see if the belt tries to ride up any pulley
This is what happens when you forget to fit the wading plug before the pay and play site!
 

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they are for the 300 tdi , its worth undoing injection pump support bracket and resecuring ensuring its not pulling on rear of the pump it can cause misalignment

Oops my mistake, had a bit of 300 target fixation. Guess that is me minus one smartie point :mad:
 
Looking at the timing casing cover it does look well polished around the injector pump sprocket? I just been out with a torch and the injector pump looks flush and bolted tight. Could it be possible that the injector pump be at fault?
 
quick way to test if to use a steel ruler edge on to the pulleys and see if there are any gaps, or maybe a large straight edge across the timing case face joints and measure from the straight edge to the pulleys measured at 4 points should give you a good idea whats going on.
Not much work to remove the pump and maybe clean the faces up and see if the support bracket comes away nicely or is under some sort of tension thus slightly twisting the pump out of square, could be engine has been dropped, or someone has used that bracket as a strap point for lifting the motor about.
 
Looking at the timing casing cover it does look well polished around the injector pump sprocket? I just been out with a torch and the injector pump looks flush and bolted tight. Could it be possible that the injector pump be at fault?

its not unkown for injection pump to be pulled towards the engine by rear support bracket, because of such lr changed support bracket on later 300tdis to stop it happening by poor fitting by mechanics
 
These suggestions sound very fesable as the garage that fitted my engine was bit of a shambles. If the injector pump had been bent by a engine hoist strap could it have bent the engine casing that it bolts to too?

Thanks for this it feels like I'm getting somewhere now.
 
Shall do. I have a week off soon so I'll tackle it then. If the pulley is at a slight angle Is there a possibility of shimming the injector pump to make it flush to the other pulleys?
 
Iv sourced a second hand injector pump, worth a try and if it doesn't work I'll have a handy spare. I will fit it along with a new belt in the next couple of weeks. I just been looking at the pics again of the casing and it looks as if the injector pump pulley may be bending inwards with the belt pressure? Could there be some bearings have worn on the injector pump causing this?
 
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Another pump wont make any difference, unless of course your present one is fooked, the amount you would have to move the pump at the back to get the belt to run out line is a matter of millimetres.
Ive changed a couple and have never had any bother with belts etc, bolt pump to timing chest make sure theres no **** between the faces then secure the bracket at the rear.
I think there may be a gasket between pump and chest ERR631
 
I started to tackle it today and when I took the timing chest off my suspicions where confirmed, I was greeted with this...

Riding over again!

U followed the helpful advice from this forum and fount the injector pump pulley toes inwards...



And also shows on the chest casing that the belt is following the angle from the injector pump pulley...



Iv had a good look at the timing casing and the injector pump pulley and nothing looks bent or damaged so would you suspect it to be the injector pump pulley bearings?

Iv got a pump on the way so I'm going to try it but I would like to hear people's opinions if it could be this?

I'll keep the thread updated incase anyone else has this problem.
 
worth checking rear pump to block support people often pull the pump towards block when tightening bolts ,because they dont nip all the bolts on pump and block equally before tightening any
 
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